Certain clinical and morphologic findings in 6 patients, all women, who underwent cardiac valve operations for combined mitral stenosis and tricuspid valve stenosis and who died within 60 days of the simultaneous mitral and tricuspid observations were summarized. Two of the 6 patients died from excessive bleeding and other 4 from 3 to 13 days from inadequate cardiac output. In 2 of the latter 4 patients the cause of the diminished cardiac output was anatomic evidence of interference with mitral occluder movement and the cause of the inadequate cardiac output in the other 4 patients was not determined from anatomic study. Combined mitral and tricuspid valve stenosis is a very unusual combination and no previous studies have described morphologic observations after simultaneous valve operations in these patients.